We plan to 1)identify subjects at risk for the development of HTN, 2)determine the influence of risk, status (HR vs NR) or ABP patterns on a normal Na+ diet and determine the influence of risk status on 24-hour hormonal patterns (PRA, PAC<ACTH) on a normal Na+ diet, 3)determine the influence of risk status on pattern of renal hemodynamics and proximal tubular reabsorption and compare the groups with regard to the relationship among the hormonal activity.